Tension device for sewing-machines



(No Model.) 2 Sheets-Sheet 1. W. DUGHEMIN.

TENSIONDEVIOB FOR SEWING MACHINES.

Patented May 9,1882.

N. PETERS, PhcloLllhngnphw. Wzshinghm, D. C.

2 Sheets-Sheet 2. W. DUGHEMIN.

TENSION DEVICE FOR SEWING MACHINES.

(N0 Model.)

Patented May 9,1882;

Ewen-60 7? UNITED STATES,

PATENT OFFICE.

WILLIAM DUUHEMIN, OF BOSTON, MASSACHUSETTS.

TENSION DEVICE FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 257,563, dated May 9, 1882.

Application filed February 9, 1862.

(No model.)

Improved Thread-Tension to be Used on. Sewing-Machines, of which the following is a specification.

My invention relates to threadtensions to be used on sewing-machines; and the objects of my improvements are to produce a tension device that can be effectually used whether attached or detached to or from the machine,

and of such natureth at the largest sized spools can be used therein with the same ease and safety from breakage of thread as the smallest,

and that will give out the thread with the same resistance without reference to the finish or uniform size of the threador spool. These objects I attain by the mechanism shown and illustrated by the accompanying drawings, in which- Figure l is a top view of the mechanism; Fig. 2, a side view; Fig. 3, a vertical section;

Fig. 4, a transverse section on line 1, Fig. 3;

Fig. 5, a top view of a modification of the (lo-- vice; Fig.6, a vertical section of the same; Fig. 7, a side view; Fig. 8, a modification of the arm, and Fig. 9 a section of metallic base to which the device is secured when detached from the machine.

Similarletters refer to similar parts throughout the several views, A representing the spool, and t the thread.

The device consists of a straight tube, which,

passing through the spool, holds it in a hori-- zontal position, in which it is secured by an uprightbar, which is attached to the machine, and a rotating head the shaft of which plays in the tube, and to which are secured side arms provided with loops, which lead the thread to a central exit in the extreme front end of the head, the tension being formed by the action of a transverse spring, which presses against the rotating head, and is constructed as follows:

i a, Fig. 3, represent a straight round shaft, having at its extreme front end a central spiral guide, a, for the exit of the thread, and on which, at a proportionate distance inward, is rigidly secured by means of a boss, d, the crossarm I) I), to the outer ends of which, reaching inward at right angles therewith, and provided with theloops w and r, are secured the arms 0 c. 9 represents a straight circular tube of such proportion that the shaft a can rotate freely therein, (see 1', Fig.3.) On its front end is secured the shoulder-plate h, on which are projecting lugs e e, to whiclris secured by the set-screw e and adjustingscrew f the trans verse tensionspring d. The rear end of said tubej fits closely in the central aperture in the block 9' which is secured on the top end of the upright postl. hen the shaft is placed in the tube j the tension-spring d, being secured in position, as shown at c f, Fig. 2, rests in a groove, 00, made for its reception in the boss (1, and retains the shaft in position, as shown at d.

To prepare the device for use, thetnbejis passed through the central opening in the spool' A and into the block j, the inner end of which being conical, the said tube is pressed into said opening and holds the spool rigidly in a horizontal position, in which it is secured by the action of the thumb-screw 7c. The thread t is then passed through the loops to, r, and a to the thread-guide ot' the machine.

In practice as the thread is used by the machine it is drawn from the spool through the loops w and r of the arms a and a ofthe head a, and the spool being stationary, the unwinding of the thread causes the head to revolve, when the tension-spring d, pressing against the boss 61, causes the necessary friction to produce a tension. It aheavy tension is required, the screwfis turned to the right; if a light, to the left.

The device constructed as described is for large spools, which, being of extra length, require a proportionate length of working-bearing for the shaft Figs. 5, 6, and 7 represent the same device constructed in a different manner, the shaft 8 being stationary and having on its rear end a thumb-nut, s, and is provided with arotatiug head, 8 having its working-bearings just in front ofa shoulder-plate, 8''. At its outer end is a central exit, 8 for the thread, and at the inner a cross-arm, n, to the outer ends of which, provided with the loops n a, are secured the arms a n, and having the projections g g, to which, by means of the screws cf, is secured a flat tension-spring, 8 which, passing into the inlet m in the head 8 (see Fig. 7,) rests in the groove on in the shafts, (see Fi 6,) and, pressing against its surface, causes the resistance required to form a tension,'and the spring, being the same width as the groove, retains the head in position on the shaft. In principle both devices are the same, the mechanical difference being that in one a stationary spring presses against a rotating shaft and in the other a rotating spring presses against a stationary shaft, and both are prepared and used in the same manner, except that the spool is secured in position by the thumb-nuts. The tension-spring may be made of round orflat steel, as may be required, and the loop made for the reception of the adjusting-screwfmust be atrifle elongated, as shown at g, Fig. 2.

When either of the devices is intended to be used detached from the machine the upright postl is secured in the metal base 1), Fi 9, and when required for la rgc spools varying in diameter the ends of the arms I) b will be tubular, as shown atn, Fig. 3, and the arms a so made (see c) that they can he set out or in, as may be required, and held in position by the set-screw n.

.It will be seen that as the thread is drawn through loops much larger than its diameter it is not liable to be influenced by any irregul-irity of its surface. Consequently the same cannot effect the tension, and, being drawn under yielding pressure from a stationary spool,

cannot unwind too freely or become entangled, and whether the spool is large or small the rethe thread.

In setting the device on machines, or to be used in connection therewith, care must be taken to lead the thread in a direct line with the shaft a 1', as the slightest departure from this rule will destroy the perfect operation of the tension.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. Ina tension device for sewing-machines, the transverse tension-spring d, adjustingscrew f,and groove .1 arranged and located as. and for the purpose described.

2. In combination, the revolving shaft 0, havinga centralspiral-formed exit, a, the crossbar I) '0, having the central boss, d, provided with the groove 00, and arms 0 0, having the loops to 1', the tubular shat'tj, having the shoulder-plate IL, with the lugs c e, the set-screw e, adjusting-screw], transverse tension-spring d, and blockj provided with the thumb-screw 7t: and rod 1, all arranged and located as and for the purpose set forth.

In testitnonywhercotI have signed my name to this specification, in thepresence of two sulr scribing witnesses, this 7th'day of February, 1882.

WILLIAM DUUHEMIN. Witnesses JOSEPH N. GoNoLLY, GEO. W ILLIS PIERCE. 

